This invention relates to an outboard motor and more particularly to a supercharger arrangement for an internal combustion engine and a cooling arrangement for the compressed air charge.
The use of superchargers to improve the performance of internal combustion engines are well known. By using a supercharger, the air delivered to the engine for its combustion is compressed so as to force a greater fuel/air charge into the combustion chamber and permit the attainment of a higher power output than atmospherically charged engines. In addition, if the engine is of the two-cycle type, the use of a supercharger can assist and improved in the scavenging action.
Because of the fact that the air charge compressed by the supercharger becomes heated, the full advantages of supercharging may not be enjoyed. That is, as the air charge is heated, the air expands and the density of the air delivered to the combustion chamber is reduced. To avoid this, it has been proposed to incorporate intercoolers that cool the air charge before it is delivered to the engine so as to improve the volumetric efficiency and further gain the advantages of supercharging.
However, there are a number of disadvantages to the use of intercoolers, particularly with certain engine applications For example, the intercooler takes up a fairly substantial amount of space in and of itself and this can render it unsuited for certain applications. For example, if the engine is a part of an outboard motor, the compact nature of the outboard motor makes it difficult to provide an effective intercooler. Furthermore, the positioning of the intercooler may interfere with the serviceability of certain components. In addition, the intercooler acts between the supercharger and the engine and the actual heat generation takes place for the most part, within the body of the supercharger itself.
It is, therefore, a principal object to this invention to provide an improved arrangement for cooling a supercharger for an internal combustion engine.
It is a further object to this invention to provide a supercharged, outboard motor wherein the supercharger has a high efficiency because it is itself cooled.
It is a further object to this invention to provide an improved supercharging arrangement for an internal combustion engine wherein the supercharger and the ducting interconnecting the supercharger with the engine are both cooled.